An aerogel is a superporous, high specific surface area (≥500 m2/g) material having a porosity of about 90 to 99.9% and a pore size in the range of 1 to 100 nm, and is a material excellent in ultra-light weight, super insulation, ultra-low dielectric, and the like. Accordingly, research on the development of aerogel materials as well as research on the practical use thereof as transparent insulation materials, environmentally friendly high temperature insulation materials, ultra-low dielectric thin films for highly integrated devices, catalysts and catalyst carriers, electrodes for supercapacitors, and electrode materials for seawater desalination have been actively performed.
The biggest advantage of the aerogel is that the aerogel has a super-insulation exhibiting a thermal conductivity of 0.03 W/m·K or less, which is lower than that of an organic insulation material such as conventional Styrofoam, and that fire vulnerability and the occurrence of harmful gases in case of fire which are fatal weaknesses of the organic insulation material can be solved.
Meanwhile, since such an aerogel has a very low mechanical strength due to a porous structure, an aerogel composite bonded by impregnating the aerogel with a fabric blanket has been developed. The aerogel blanket is flexible and can bend, fold or cut in any size or shape, and is easy to handle. Therefore, the aerogel blanket is used not only for industrial uses such as insulation panels for LNG carriers, industrial insulation materials and spacesuits, transportation and automobiles, insulation materials for electric power production, but also for daily necessities such as jackets and sports shoes.
Aerogels are generally produced through the steps of producing, gelling, aging, surface modifying and drying a silica sol. Conventionally, in order to improve the insulation and fire prevention characteristics of the aerogel blanket, an additive such as a metal hydroxide-based flame retardancy is used for reducing radiative conductivity in the silica sol production step and improving flame retardancy performance.
However, due to adding the additive, the SiO2 bond was weakened to reduce an adhesive force between a blanket substrate and an aerogel, thereby increasing the generation of dust. When the aerogel blanket was applied to a pipe or the like, the aerogel was continuously separated from the blanket substrate due to vibration of the pipe, so that the aerogel separation phenomenon was further deteriorated due to the use of the additive.
In order to solve the problem, U.S. Pat. No. 8,021,583 B2 has tried to produce aerogel granules or powders to fill them between fibers in the form of slurry, thereby reducing the generation of dust, but there was a problem that the thermal conductivity was increased due to a binder or the like, compared with a gel casting method.
Accordingly, the inventors of the present invention have invented a method for producing a low-dust, high insulation aerogel blanket capable of reducing the generation of dust while having excellent flame retardancy and thermal conductive performance, and a low-dust, high insulation aerogel blanket produced thereby.